The following picture shows the construction of of an angle dormer sash and case window made to suit a property in Edinburgh.
Here we see a haunched tenon on the bottom rail.
Bottom rail shown with tenons.
Dry-fitting bottom sash.
Cleaning out a mortise.
Bottom rail mortise and tenon shown with wedge relief.
Final glue up.
Test fitting sashes inside case.
Checking mid-rails for alignment.
Finished angled sash and case.